William kester



straight. When this form of apparatus is used, the cars arevimpellcd by hand, an operator standing at each endof the track. The operator at K pushes the car through to his companion at L, who turns the slates, and pushes it back. When this arrangement is employed, a track maybe laid under each side of the grinding-stone.

'Machinery which will give the cars a reciprocating motion maybe employed, instead of hand-power, if preferred, but, as the'slates must be inserted, turned, and removed by-hand, it is presumed that hand-,power will be even more economical and convenient for the purpose than other motive-power.

Revolving disks working upon vertical shafts have been for years employed for rubbingdown slate. I lay no claim in this connection to the use of'snch stones or disks, nor to the arrangement of gearing by which they are driven, nor yet` to their arrangement around thccircular bed; neither do I broadly claim the use of cars runningon a circular or `straigl1ttrack, to 'carry andr apply the slates to such grinding-stones.

My claim in this invention, is limited entirely' to the devices for preserving the level Vof the cars while they rise towards and recede from theunder surface of the grinding-stones, and to the useofl the upper or movable plate or bed. f the cars.

Having thus described my invention, I may set forth more definitely what I claim as new, and desire to secure by Letters Patent, as follows: l I

1. The track blz', when composed of the double inelincs-t t', and used in connection with the cars G G and v grinding-stones'D D, in the manner and for the purps'e'specicd.

2. The combination of the movable bed H, springs s s, and body ofthe cai` Grubstantially as and for the purpose specified. l

WM. KESTER.

Witnesses:

CHAs. A. PETTIT, SoLoN KEMoN. 

